{"id":1080,"date":"2022-10-26T11:26:10","date_gmt":"2022-10-26T15:26:10","guid":{"rendered":"https:\/\/techfragments.com\/?p=1080"},"modified":"2022-10-26T11:26:10","modified_gmt":"2022-10-26T15:26:10","slug":"ixpe-hercules-x1-polarization","status":"publish","type":"post","link":"https:\/\/techfragments.com\/ixpe-hercules-x1-polarization\/","title":{"rendered":"IXPE\u00a0Measures X-ray Pulsar Hercules X-1 Polarization"},"content":{"rendered":"

Hercules X-1, a neutron star<\/a> floating in a galaxy 21,000 light years away, has had its geometrical parameters identified by researchers from the University of Turku. The discovery supports previous theories that this star’s precession is like a whirligig.<\/p>\n

Strongly magnetized neutron stars called X-ray pulsars are among the most well-known sources of X-ray light. They are powered by the accretion of gas from a nearby companion star.<\/p>\n

The recently launched Imaging X-ray Polarimeter Explorer<\/a> (IXPE) space observatory, which began operations at the end of 2021, offers a fresh perspective on these objects. IXPE measures X-ray polarization, and it was used to determine the polarization from an X-ray pulsar for the first time, allowing for the constraint of the pulsar’s fundamental geometry.<\/p>\n

“Hercules X-1 was the first X-ray pulsar observed by IXPE, and a very low polarization we observed came as a big surprise and that is something we still do not fully understand,”<\/p><\/blockquote>\n

Victor Doroshenko of the University of Tuebingen in Germany, the study’s lead author, stated.<\/p>\n

Polarization Lower Than Predicted<\/h2>\n

It turned out that the average degree of polarization, which was measured by IXPE with extremely high accuracy and was around 9%, was significantly lower than the theoreticians’ overly optimistic prediction of 80%.<\/p>\n

“Such a large discrepancy implies that existing models of radiative transport in strongly magnetized plasma confined at the poles of a neutron star and our ideas regarding geometry and structure of the emission region in Hercules X-1 and possibly other pulsars will need to be substantially revised in light of IXPE results,”<\/p><\/blockquote>\n

said Juri Poutanen from the University of Turku in Finland.<\/p>\n

It was possible to measure the angle between the spin and magnetic dipole axes by observing variations in the polarization angle over the spin phase. This information is essential to any modelling of emission from such objects.<\/p>\n

Whirligig Precession<\/h2>\n